Help on real-time Display

The Real-Time Display has 4 screens.

Use the PgUp and PgDn keys to switch between them.
   
The first screen is the main screen  called the engine monitor screen and it shows all the main 
inputs and  outputs of the ECU.(Press PgDn whilst in help to find HELP for other real-time 
screens)
The second screen is the electrical fault status screen and it shows the ECU fault diagnostics.
The third screen shows the throttle pot readings in large text to aid throttle pot setting.
The forth screen shows the closed loop fuel control status.

Screen 1 - ENGINE MONITOR SCREEN
INPUTS -
ENGINE SPEED
Engine speed is displayed in RPM and it should correspond to actual engine speed.  Spurious 
or non-existent readings denote a faulty sensor or sensor wiring. Check sensor for damage, 
metal debris on its end, corrosion or water in its terminals, and correct polarity (see wiring 
diagram )
THROTTLE POSITION
Throttle position is displayed as a percentage of throttle potentiometer movement.
15% corresponds to a fully shut throttle, 94% to a fully open one. There are two throttle 
position sensors, one for each  set of three cylinders. Page down to the third real-time screen 
to display throttle pot. readings only. Throttle pot readings  should be equal on both banks to 
within a few percent, and must not fluctuate more than 3%. The readings  should increase 
smoothly with increasing throttle travel. If a fault is detected with one of the throttle pot 
readings it will substitute the value from the other throttle  pot, so they will both display 
EXACTLY THE SAME READING.

The throttle position sensor is NON ADJUSTABLE  on all 6 cylinder engines . If the throttle 
potentiometer is replaced , or the throttle linkage is adjusted in any way , the closed throttle 
position should be reset . This is done from the ECU TOOLS menu by clicking on reset 
throttle. This must only be done when the throttles are in the idling position. The idling 
position will be monitored by the ecu and re-adjusted to maintain the minimum position to 
approx. 15%.  
AIR TEMP
Air temperature is measured by the sensor located  next to the air filter. If the ECU detects a 
fault with this reading it will substitute a value of 10 degrees °C .
WATER TEMP
Water temperature is measured by the sensor  located in the cylinder head. If the ECU detects 
a fault with this reading it will substitute a value of 95°C. The engine cooling fans are 
controlled by this temperature reading, and are  turned on at 92°C, off at 88°C. 
Therefore under fault conditions  the cooling fans will be turned on.
BATTERY VOLTAGE
Battery voltage is displayed in volts. It should normally read between 12.0 & 13.8 V There is 
no default value.
BAROMETRIC PRESSURE
Barometric pressure is measured from the left hand air box and is displayed in mBAR. It 
should correspond to the air pressure as measured on a barometer. If the ECU detects a fault 
with this reading it will substitute a value of 1000 mBAR. The pressure sensor is mounted 
inside the car to protect it from excessive heat. If incorrect readings are displayed, check the 
pipe between the sensor and airbox for blockages or leaks.
LAMBDA 1 & LAMBDA 2
Lambda 1&2 show the signals from the lambda sensors on each set of three cylinders. 
Lambda1 is the front three cylinders (ie. cylinders 1,2&3) and lambda 2 is the rear three 
cylinders (ie. 4,5&6 ). After starting the sensors will take at least 30 seconds to warm up, 
before  they will read correctly . Once warmed up, the lambda signals should switch between 
approx. 0 & 1-1.5 volts. 0 volts shows that the fuel mixture is lean, 1 volt shows that the 
mixture is rich. The rate of switching will alter with engine speed, and the percentage of time 
spent rich relative to lean will alter with engine load. If reading is a CONSTANT 0 V, check 
sensor for proper connection, and sensor heater wires for continuity (6 ohms between white 
red wires)
NOTE: Lambda sensors are supplied with 12V on the red wires ONLY WHEN THE FUEL 
PUMP IS  RUNNING, the WHITE wire is earth and BLACK the signal.

OIL PRESSURE
Oil  pressure is measured from the oil pressure sensor mounted on the inner wing under the 
air box. The output from the oil pressure sensor is used to turn on the oil pressure warning 
light at low pressures at low RPMs, and at higher pressures at higher RPMs
If the wire from the sensor to the ecu is disconnected or broken the pressure reading shown 
will be approx 130 psi.and the warning light will be PERMANENTLY off.
If the wire from the sensor to the ecu is shorted to ground  the pressure reading will be approx 
150 psi and  the warning light will be PERMANENTLY off 

OUTPUTS
FUEL 1 & FUEL 2  	                 
Fuel injection time is displayed for each bank. When water temp >80°C at idle it
should be between  2.2 & 2.4 ms. Higher readings than this could indicate misfiring
due to fouled plugs, incorrectly balanced throttle assemblies, or faulty lambda
sensor readings. Check primary exhaust pipe temperatures to detect poorly running
cylinders, (a chinagraph pencil touched  on the exhaust manifold 1 inch from the port
 face works  well) and check cylinder airflow with syncrometer to detect poor balance. 
If all cylinders are running correctly check  lambda sensors as above, replace if
faulty. If a cylinder is still not running properly, disconnect the suspect injector
and connect the injector circuit tester. Start the engine and run for A FEW SECONDS
ONLY. If the injector circuit is OK, then the tester will flash whilst the engine is 
running. DO NOT RUN THE ENGINE FOR EXTENDED PERIODS WITH THE         
INJECTORS DISCONNECTED, AS SERIOUS DAMAGE TO THE CATALYTIC 
CONVERTERS WILL 
OCCUR

ADAPTIVE 1 & ADAPTIVE 2
These numbers represent the percentage by which the ECU has adjusted the amount of fuel 
being injected in order to achieve the correct mixture. There are adaptive values for every  
combination of speed and load, which will change independently of each other. If the engine 
is running correctly this percentage should be low. If it is high ( >+/-20 percent) then a fault or 
maladjusted throttle pot should be suspected. Typical faults could be:
Incorrectly fitted or damaged HT leads (lubricate the Ht lead boots with WD40 	 
before fitting, and ENSURE YOU HEAR THE RETAINING CLIP  "CLICK"                                                                                                      
ONTO THE  SPARK PLUG TOP.)                                                                                
                   Air leak into intake or exhaust manifolds                                                                                                                                  
                   Damaged or badly fouled spark plugs                                                                                                                                  
                   Damaged injector wiring (test with injector wiring tester)                                                                                                  
                   Excessive purging due to high fuel temperatures                                                                                                      
                   Carbon Can or purge lines contaminated with liquid fuel 
IF A CAR HAS BEEN RUNNING BADLY WITH FAULTS PRESENT, THE ADAPTIVE 
MAPS MUST BE RESET TO ZERO. This is done by selecting "ZERO ADAPTIVE MAPS" 
from the ECU TOOLS menu.
Disconnecting the ECU does not erase its memory on 941 series ECUs! 
IGNITION
Ignition timing is displayed in degrees before TDC. At idle, with coolant temp above 80 C , it 
should be between 12 & 17 degrees. If it is not, check all inputs for correct readings, and 
check idle speed is set at 950 RPM


FUEL PUMP
This denotes if the ECU has turned on the fuel pump. It does this by grounding pin 25 of the 
ECU, which completes the circuit for the fuel pump relay, thus turning the relay on. If the 
pump appears turned on by the ECU but does not work, check to see if the inertia switch has 
tripped (the MIL lamp will turn on for 3 seconds when ignition is turned on.)  The inertia 
switch is located in the boot above the fuel tank.  If the fuel pump still doesn’t work, check on 
a cerbera that the relay No. 4 has a 12V supply to pins 85 & 30/51, if it does not check fuse 
19.
NOTE! The fuel pump relay must be a twin make (brown) relay. 
RAD FAN
This denotes if the ECU has turned on the radiator cooling fans. It does this when the water 
temp input is above 92°C for Fan 1, 94°C for Fan 2, or if a fault is present in the water temp input. 
ECU pins 6 & 41 are grounded, to turn on the cooling fan relay(s).  If the fans appear turned 
on by the ECU but do not work, check, on a Cerbera, that:
the fan relay 1 & 7 has a 12V supply to pins 85 & 30/51, if it does not, check fuse 1 , 3 and 
20.
     Screen 2 - ELECTRICAL FAULT STATUS SCREEN

This screen shows any input faults that the ECU has detected. Current faults are shown at the 
top, logged faults below.
Logged faults are ones that have been detected in the past and may or may not still be present. 
NOTE: FAULTS WILL BE LOGGED IF ANY SENSOR WIRES ARE DISCONNECTED 
WHILST THE IGNITION IS TURNED ON!
Current faults will turn the MIL lamp on. Logged faults will not.
Observing the logged faults can be useful when tracing intermittent faults. 
 Logged faults can be removed by using the ECU Tools menu, or by connecting the fault code
 diagnostic box to the diagnostic plug adjacent to the ECU connector, turning the immobiliser
 off, and the ignition on. Then press and hold the black button on the diagnostic box for at 
least
 three seconds.

THROTTLE 1 or 2 FLT
These faults are shown if the throttle pot readings are out of range. Throttle 1 is for                                                                                                                                                                                                
set 1 (cylinders 123 ) , throttle 2 is for set 2 (cylinders 456 ) If a fault is detected on one set, 
then that input signal will be ignored, and both banks will be run using the “good” throttle pot 
signal from the other set. The MIL lamp will be turned on. 
Throttle pot faults
      can be caused by:   Water ingress into throttle pot, its connector or wiring.
                                      (usually due to the use of a power washer)
                                      Corrosion on throttle pot connectors.
                                      (only use TVR gold plated connectors and throttle pots)
                                      Mechanical damage to pot or wiring.
                                      Throttle pot worn or “noisy”
                                                          
WHEN A THROTTLE POTENTIOMETER IS REPLACED, IT MUST BE SEALED ONTO 
THE THROTTLE BODY USING A SMALL AMOUNT OF SILICONE SEALANT TO 
PREVENT WATER INGRESS. .             
WATER FLT     
This fault is shown if the water temperature signal is out of range. If it occurs, a water temp of 
95 C will be substituted, the cooling fans will be turned on to prevent overheating, and the 
MIL lamp will be turned on.                        
     Water fault can
      be caused by:       Water ingress into the water temperature sensor’s connector
                                    or wiring
                                    Mechanical damage to sensor or wiring
                                    Corrosion on sensor terminals or connector
                                    Faulty sensor   
                          
AIR FLT
This fault is shown if the air temperature signal is out of range. If it occurs, an air temp of 10 
C will be substituted, and the MIL lamp will be turned on.
     Air fault can 
      be caused by:        Water ingress into the air temp sensor’s connector or wiring

                                    Mechanical damage to sensor or wiring

                                    Corrosion on sensor terminals or connector
                                    Faulty sensor

BARO FLT
This fault is shown if the barometric pressure signal is outside its normal range.  If it occurs, 
an atmospheric air pressure of 1000 mBAR will be substituted, and the MIL lamp will be 
turned on.
      Barometric fault
      can be caused by:    Kinked, broken or blocked barometric sensor pipe 

                                    Excessively clogged air filter

                                    Mechanical damage to sensor or wiring

                                    Corrosion on sensor terminals or connector

                                    Faulty sensor 

BAT FLT
This fault is shown if the battery voltage  falls below 11 V, or rises above 17v whilst engine 
speed is above 1500 RPM.
Battery fault 
can be caused by:     Faulty alternator causing over or under charging.
                                Faulty battery .
                                Poor earths from ECU to battery
                                Poor power feed to ECU from battery.






 LAMBDA 1 & LAMBDA 2
These faults are shown if the lambda sensor signal rises above 1.7V. If it occurs the MIL lamp 
will be turned on. Correct operation of the lambda sensors is best checked by viewing the real 
time logging screen. The sensor signal should alternate between 0 V and  1-1.5 V and never 
stay at a mid voltage (0.4-0.7V) position.
Lambda 1 is the front set of cylinders (ie. 1,2&3) and lambda 2 is the rear set (ie.4,5&6)
     Lambda fault
     can be caused by:     Water ingress into the lambda sensor’s connector or wiring.

                                     Mechanical damage to sensor or wiring , causing a short
                                     between the supply and signal wires.

                                     Faulty sensor    


AFR 123 & 456 FLT
These faults are shown if the adaptive values have reached their limits for CYL 123 or CYL 
456, i.e. the system has attempted to adjust the mixture by an excessive amount.  If either 
occur the MIL lamp will be turned on.
AFR fault can
be caused by:        Misfire due to ignition fault (check HT leads are correctly fitted to all 	  
	        spark plugs and coil connectors, and that spark plugs are in good condition)

                            Broken or shorting injector wiring (check using injector wiring tester)

                            Excessive fuel pressure ( > 58 psi )
 
                            Air leaks in exhaust or inlet manifold.
                           Liquid fuel in purge system (check that the fuel tank breather pipe is higher                                   
		          than  the filler cap, and that the carbon can is empty of liquid fuel)
                           Excessive purging due to overheating  fuel (check fuel pipe routing for heat       
		          pickup, insulate or reroute as required)                                                               
                           Incorrectly adjusted or faulty throttle potentiometers (check readings)
                           Faulty lambda sensors, or lambda sensor wiring.

CRANK WIRING
This fault is shown if the crankshaft speed sensor is incorrectly wired up. Check polarity and 
reconnect as shown in wiring diagram (black to pin 1 on sensor and to pin27 on ECU ,white 
to pin 2 on sensor and to pin 12 on ECU )   
                
CRANK SENSOR
This fault is shown if the crank sensor signal is poor. If it occurs the MIL lamp will NOT be 
turned on. It may however flash as a poor signal is detected, depending on the severity of the 
fault. 
Crank sensor fault 
can be caused by:       Debris on end of crank sensor (remove and clean)

                                  Water ingress into sensor connector or wiring Corrosion on sensor
    			      terminals (clean or replace connector terminals using only gold plated 
                                   terminals.
                                  Damaged trigger wheel on flywheel.
                                  Damaged crank sensor  wiring (replace ONLY WITH SPECIAL 
                                  CRANK  SENSOR WIRE)


           screen - 3 - THROTTLE POT SETTING SCREEN
       This screen shows the readings from throttle pot one (at the top of the screen) and throttle pot 
two (below) in large text . This enables you to see the throttle pot readings from a large distance .
 The throttle pots should maintain a reading of appox. 15%  WHEN THE ENGINE IS IDLING 
AT 900-950RPM..

If they do not , reset them from the ecu tools menu . DO NOT ADJUST ON THE ENGINE

    The throttle pot inputs are very sensitive and may be subject to a certain amount of electrical 
noise (+/-2%)  this is normal . Noise may also be generated by wear in the throttle spindles which 
allows the spindle to vibrate in time with the pulsing of the engine. However if this “noise” is 
excessive the ECU  may start to add acceleration enrichment fuel. If this occurs (observe 
dTHROTTLE box in the AFR STATUS SCREEN) check that the HT leads are in good condition, 
FITTED TO ALL THE PLUGS CORRECTLY and NOT TY-WRAPPED  TO THE MAIN 
ENGINE HARNESS.

This fault is most likely to occur on older or high mileage cars and can cause an MOT emissions 
failure if it is bad enough to prevent closed loop lambda control from working during the test.
 
 Change the throttle pot if this fault persists and check for excessive throttle spindle wear.  


                      Screen - 4 - AFR STATUS SCREEN
This screen shows in more detail the workings of the closed loop fuel system. 
       It should be viewed to establish that system is working correctly.

		In order to work correctly, the catalytic converters must be supplied with exhaust gas from 
chemically correct combustion. This means that the air fuel ratio must be maintained at 14.7:1 
This is done by using LAMBDA sensors in the exhaust gas to measure whether combustion 
was rich or lean. When in a "rich" gas, the lambda sensor will read approx 1-1.5V (provided it 
has warmed up) When in a "lean" gas, it will read approx 0V.  
		If it was rich the ECU reduces the amount of fuel to be injected at the particular speed and 
load that the engine was at, when the exhaust gas being measured, was created.  If the mixture 
was lean, the ECU would increase the amount of fuel to be injected.  This adjustment is 
remembered as an adaptive value. There many adaptive values created for all combinations of 
speed and load. Thus the ECU "retunes" the engine throughout its life to maintain optimum 
performance.
		Before lambda control can begin the lambda sensors must be allowed to warm up. This is 
shown in the warm up timer box, and should last for approx. 30 seconds.
		The engine temp must also be high enough to maintain combustion at an AFR of 14.6:1. 
This is shown by the water temp box.
		In order to accelerate cleanly without missing a richer mixture is required. This is 
provided when rate of change of throttle position (dTHROTTLE) is detected. So, close loop 
control is suspended whilst dTHROTTLE is present.
		Very rapid changes in engine speed make reliable closed loop control impossible, so it is 
also suspended under these conditions, as shown in the dSPEED box.  
		When running correctly, the lambda voltages should switch between 0 & 1-1.5V 
(approx.). When under light load these voltages will stay predominantly lean (0V), with rich 
spikes (1V). 
       As the load increases the engine should tend towards equal periods of running rich and lean.
       As the throttle position tends towards fully open (>69%), closed loop control will be 
suspended in order to maximise performance. This is shown in the LAMBDA CONTROL box. 

